If you are using lftp to connect to a secure FTP (SFTP) server using SSL, you may sometimes get the following error during file transfers:
534 Protection level negotiation failed.
In this case, you need to add the following line to the bottom of your /etc/lftp.conf file
set ftp:ssl-protect-data
Now try connecting again and hopefully everything should work ok – it sorted my problems when I was trying to connect to the Leeds University SFTP servers using lftp on Ubuntu 9.10 (Karmic).
情况
由于最近在中国某个地方爆发了 riot, 所以境内很多网站又是无法访问 (twitter.com、facebook.com 等)，让我们这些网民很无奈。
使用 SSH 翻墙
我曾经介绍过如何使用 SSH 来建立一个 SOCKS 代理服务器，让你能够在 Firefox 里正常访问以上所提起的网址。然而不是所有 Linux 软件都能支持代理服务器。如果你最热爱的 Linux 工具需要访问”被封”的网站，又没有嵌入的代理支持，该怎么办呢？
遇到这种情况当然不要放弃该软件… 毕竟我们用的系统是 Linux 而不是以前让我们咳声叹气，丧失信心的 Windows，总有一个方法去解决问题。
举个例子吧
我不久前发现了 Twitter 这个网站。我一开始不经常用，也搞不明白别人为什么对这个 web 2.0 服务都着了迷。后来我在推特上跟的人越来越多，跟着我的人亦是日益增多，不知不觉我也迷上了该网站，天天都会上。凡是经常用推特的人一般都会用一个推特的客户端，这才能跟得上朋友们的状态更新和最火热的网络新闻。本人作为 Ubuntu 的用户，我自然就选了 Gwibber 这个基于 GNOME 的客户端来访问我的推特。这个软件功能很丰富，用起来得心应手，不过总有一个问题让我有点遗憾，就是 Gwibber 还不听从 GNOME 的代理设置。平时这也不是一个很大的问题，但是每遇中国网络封锁较严重时，都会让我暂时无法使用该软件。
解决方案… Tsocks
经过几个 Google 搜索，我最终很高兴地发现 Linux 有一个能够强迫任何软件通过 SOCKS 代理上网的工具，其名就是 tsocks。Tsocks 是一个透明 SOCKS 代理软件，只要你电脑有一个连接到国外服务器的 SSH 隧道，你就能让任何软件翻墙。
安装并配置 Tsocks
以下说明都是为了那些使用 Ubuntu 的 Linux 用户，不过在别的 Linux 发行版下，安装的过程应该与此差不多。
在终端中:
sudo apt-get install tsocks
修改配置文件:
sudo nano /etc/tsocks.conf
将其内容改成以下几行并保存退出:
local = 192.168.1.0/255.255.255.0 #local表示本地的网络，也就是不使用socks代理的网络 server = 127.0.0.1 # SOCKS 服务器的 IP server_type = 5 # SOCKS 服务版本 server_port = 9999 ＃SOCKS 服务使用的端口
你可能需要修改一下以上内容，用你自己的 SSH 隧道设置。
运行软件
用 tsocks 运行你的软件很简单，在终端中:
tsocks 你的软件 &
我现在运行 Gwibber 都是这样运行的:
tsocks gwibber &
祝你们翻墙愉快！
EDIT—————–>
我今天还发现了另外一个工具，其功能似乎比 tsocks 要更丰富，配置起来更简单，而且不会那么容易出错。这个工具就是 proxychains。以下有配置方法:
sudo apt-get install proxychains
修改配置文件 (/etc/proxychains.conf)，应该如下：
# proxychains.conf VER 2.0 # # HTTP, SOCKS4, SOCKS5 tunneling proxifier. # # The option below identifies how the ProxyList is treated. # only one option should be uncommented at time, # otherwise the last appearing option will be accepted # # Dynamic - Each connection will be done via chained proxies # all proxies chained in the order as they appear in the list # at least one proxy must be online to play in chain # (dead proxies are skipped) # otherwise EINTR is returned to the app # # Strict - Each connection will be done via chained proxies # all proxies chained in the order as they appear in the list # all proxies must be online to play in chain # otherwise EINTR is returned to the app # # Random - Each connection will be done via random proxy # (or proxy chain, see chain_len) from the list # this option is good for scans dynamic_chain #strict_chain #random_chain # Make sense only if random_chain chain_len = 2 # Quiet mode (no output) #quiet_mode # Write stats about good proxies to proxychains.stats #write_stats #Some timeouts in milliseconds # tcp_read_time_out 15000 tcp_connect_time_out 10000 [ProxyList] # ProxyList format # type host port [user pass] # (values separated by 'tab' or 'blank') # # # Examples: # # socks5 192.168.67.78 1080 lamer secret # http 192.168.89.3 8080 justu hidden # socks4 192.168.1.49 1080 # http 192.168.39.93 8080 # # # proxy types: http, socks4, socks5 # ( auth types supported: "basic"-http "user/pass"-socks ) # #http 10.0.0.5 3128 socks5 127.0.0.1 9999 socks4 127.0.0.1 9050
注意事项:
运行 proxychains
运行 proxychains 跟运行 tsocks 完全一样。在终端中:
proxychains 你的软件 &
比如说:
proxychains chromium-browser &
我还是推荐你使用 proxychains！
我曾经介绍过如何使用 Amazon EC2 建立自己的代理服务器来“翻墙“。用这个方法翻墙虽然网速很快，但还是有些缺点。Amazon EC2 是收费的，而且按小时算，所以不能随时都开着我的代理服务器。另外，每次想用代理的时候还得先等一两分钟，让服务器启动。
然而我今天看到了这个贴子，这才发现还可以使用一个普通的网站主机作为我的代理服务器。与 Amazon EC2 不同，普通的网站主机是 24/7 运行的，而且你本来就要用它做你的网站，不用额外花钱。以上帖子是专门写给使用 Dreamhost 的 Windows 用户。不过，凡是有支持 SSH 服务网站主机的 Linux 用户也可以享受翻墙的自由感。我为 Linux 用户编了一个小的 BASH 脚本，其主要功能为:
用这个脚本，我试了一下上平时被 GFW 封杀的 youtube.com… 结果 Firefox 差点让我晕倒了! 用这个代理，网速快极了… 感觉好像我还在英国上网似的 (那边一般都用 8M 以上的宽带) – 你可以看一下视频:
介绍一下脚本的内容
export SSH_HOST=admin@yoursite.com # username@host
这个需要你自己改一下… 就是你的 webhost 给你的 SSH 用户名和主机地址。 格式为 用户名@地址 （凡是用过 SSH 的人都应该知道写什么）
if [ ! -f /tmp/.tunnel ]
看看是否已经有 SSH 隧道开着。有的话就将其关闭。没有就创建新的 SSH 隧道。
ssh -f -D 9999 $SSH_HOST "if [ -f ~/.tunnel ]; then rm ~/.tunnel; fi; while [ ! -f ~/.tunnel ]; do echo > /dev/null; done" &
创建新的 SSH 隧道，设定本地 SOCKS 端口为 9999。隧道将会开着直到远程目录 “~/” 里有人创建 .tunnel 此文件为止。
touch /tmp/.tunnel
在你的电脑上创建 .tunnel 这个文件。这样脚本就知道正开着一个 SSH 隧道。
ssh $SSH_HOST "touch ~/.tunnel"
在远程目录 “~/” 里创建 .tunnel 此文件，这将会断开你电脑与代理服务器的连接
rm /tmp/.tunnel
删除 .tunnel 这个文件。这样脚本就知道 SSH 隧道已关闭。
下载并执行脚本
可以在此下载脚本
下载后放在你的首目录，比如在 ~/bin/。用一个文字编辑器修改脚本里的 ssh 变量并用 chmod 改一下文件权限
chmod u+x tunnel.sh
创建连接
在终端中执行脚本，执行后可以关闭终端。
关闭连接
再次在终端中执行脚本并关闭 Firefox (如果 Firefox 还在用隧道的话，连接暂时无法关闭)
用 SSH 密钥进行授权
你或许注意到了… 以上脚本里没有任何地方可以写下你的 SSH 密码。这就是因为我在用 SSH 密钥来进行电脑与服务器的授权工作，这样更自动化而且比将密码直接写入文本的文件里要安全多了。先打开一个终端，根据一下步骤进行密钥配置:
[jonolumb@jonoxps .ssh]# ssh-keygen -t rsa Generating public/private rsa key pair. Enter file in which to save the key (/home/jonolumb/.ssh/id_rsa): Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/jonolumb/.ssh/id_rsa Your public key has been saved in /home/jonolumb/.ssh/id_rsa.pub The key fingerprint is: h7:10:49:46:ab:2t:3b:a3:36:2z:15:56:d4:f2:b7:3d jonolumb@jonoxps
请注意，配置时密码要留为空白。
将生成的 /home/jonolumb/.ssh/id_rsa.pub 的内容复制到远程服务器目录下，具体位置是:
~/.ssh/authorized_keys
要保证远程的 authorized_keys 和 本地的 id_rsa 文件的权限均为 700。
这样就可以自动登录到远程服务器了。
配置 Firefox 使用代理
创建了 SSH 隧道之后，就进入 Firefox 并打开:
首选项 --> 高级 --> 连接设置
选择“手动配置代理”并将其设定为:
HTTP 代理: localhost 端口: 9999
如果你用这个脚本遇到什么问题，请跟我取得联系。我很想听你们的意见。谢谢！
A new version of Gnome-Do was released today – 0.8.2. However, don’t be deceived by the small change in version number, this new release contains plenty of new features as well as squashing quite a few bugs along the way. Here is a brief summary of some of the changes I’m aware of.
Docky ‘Intellihide’ Feature
Previously when using Docky at the bottom of the screen, you had two options. You could either have the dock open permanently or you could enable the auto-hide feature. Having the dock there permanently certainly facilitates speedy opening of programs but in reality, it is hardly ideal – what with it getting in the way of all your windows and not allowing you to click on anything at the bottom of the screen. The autohide option is probably the way most people went – but this means that the dock is never visible until you drag the mouse pointer down to the bottom of the screen – which makes opening programs using the dock rather cumbersome.
This contradiction has now been resolved with a new feature called ‘intellihide’. If selected, the dock will automatically hide itself when there are full screen programs open on the desktop or when windows are too near the bottom of the screen. However, Docky can still be accessed at all times by dragging the mouse down to the bottom of the desktop. If no programs are open on the desktop and nothing is blocking the bottom of the screen, Docky will pop back up again and stay at the bottom of your screen allowing you fast, easy access to your most used programs when you need them.
Docky Top and Bottom Orientation
Whilst previously Docky could only be placed at the bottom of your screen, you can now have your favourite dock floating around at the top of your screen now – giving you even more possibilities for desktop customisation.
Improved Flickr Uploading
The Flickr upload plugin now provides more feedback on upload progress. Unlike previously where there would simply be a Gnome-Do icon displayed in the system tray, the Flickr uploader now has it’s own window and tells you when the upload has completed successfully.
Better UI and Graphics Perfomance
Your mileage may vary depending on what hardware and drivers you are using but I have noticed that the dock animations seem much smoother than before. Furthermore, there are some lovely coloured lighting effects on dock icons for the application which is active in the current window. You can now also change the zoom and icon size settings with sliders rather than dragging “handles” on the dock itself.
Docklets
I’ve tried installing this feature with:
sudo apt-get install gnome-do-docklets
But it says that it can’t find this package or something along those lines. It sounds like an exciting feature but I’ll have to wait until I can get it working before I can provide more details. All I can find at the moment is information about a nifty looking Weather Docklet which is documented on the Do Wiki.
Apart from the things I mentioned above, there are now a lot of new plugins available for Gnome-Do and localisation is better than before – with most of the program and some plugins now available in other languages. There are probably plenty of other things that have so far gone unnoticed so please leave me a message in the comments if I missed anything important.
